Project Summary/Abstract Alzheimer?s disease takes many years to progress and it is unclear about the early stage of development of disease onset. Neural cell dysfunction and cell death in neural degeneration cause the memory loss and harm the ability to learn for the patients. Therefore studying the disease progression and the identification of drugs that can treat Alzheimer?s disease are important to relieve the financial and emotional burden for the society. Current challenge of in vitro human brain models is the difficulty of recapitulating the brain regions, i.e., specific cortical layers and hippocampus, which are the most affected areas by Alzheimer?s disease. Human induced pluripotent stem cells (hiPSCs) derived from fibroblasts of the patients have the ability to self-assemble into forebrain-like structure that retains the patient?s genetic background when the proper microenvironment is provided to the cells. This 3-D culture that mimics human brain structure is better to promote mature neural function and recreate Alzheimer?s disease pathology compared to 2-D culture. The objective of this proposal is to establish a novel in vitro Alzheimer?s disease model using 3- D forebrain organoids derived from hiPSCs for identifying therapeutic targets in extracellular matrix (ECM) proteins. The central hypothesis is that modulating heparan sulfate proteoglycans and matrix metalloproteases attenuates Alzheimer?s disease-associated neuropathology in hiPSC-derived 3-D forebrain organoids. Specifically, the following aims are proposed: 1) to test the hypothesis that hiPSC-derived ECMs recapitulate microenvironment change in normal or diseased cortical organoids. 2) Aim 2 will test the hypothesis that modulating heparan sulfate proteoglycans and matrix metalloproteases reduces neural degeneration in cortical organoids. The novelty of the proposed research is that the forebrain organoids derived from hiPSCs provide the 3-D cortical layer-specific structure that not only recapitulates the complexity of human brain (compared to standard culture models), but also retains patient-specific genetic background (compared to animal models). In particular, the derived forebrain organoids allow the modulation of ECM microenvironment to investigate and attenuate neural degeneration.